Various publications, including patents, published applications, technical articles and scholarly articles are cited throughout the specification. Each of these cited publications is incorporated by reference herein, in its entirety. Full citations for publications not cited fully within the specification are set forth at the end of the specification.
Plants of a wide variety of species have been used for health promoting and particular medicinal purposes for many thousands of years. In recent years, research has revealed that plant-based phenols, flavonoids, isoflavones, terpenes, glucosinolates and other compounds present in fruits, vegetables and leafy herbs, among other types of plants, possess antioxidant and anti-carcinogenic properties, among other health-promoting benefits. Among certain aromatic herbs, such as mints and oregano, essential oils and extracts have been found to contain antiseptic, antimicrobial, anti-inflammatory and antiviral agents.
Due to the ever-growing consumer preference for natural products and remedies, the value of plant derived therapeutic agents has increased steadily. Moreover, the more traditional value base of certain plant components, e.g., for the flavor and fragrance industry, has remained robust.
Essential oils constitute one type of valuable plant component. An essential oil is a concentrated, hydrophobic liquid containing volatile aromatic compounds, obtained by distillation from various plant parts. Essential oils are used in perfumery, aromatherapy, cosmetics, incense, for flavoring food and drink, and in medicine. The medicinal value of certain essential oils can be considerable. For instance, the essential oils of oregano, which primarily contains carvacrol, thymol and p-cymene, is a powerful antibacterial and antimicrobial agent.
Essential oils are produced by water or steam distillation. Typically, the plant material is immersed in water and boiled, or exposed to steam flow. The steam and oil vapor is condensed and the oil is separated from the water. Customarily, the residual plant material is discarded once the essential oils have been distilled, on the assumption that the material would not yield additional components or substances of appreciable value once it has been subjected to the distillation process.